GM Service Manual Online
For 1990-2009 cars only

While sitting in a comfortable driving position, adjust the mirror so you can see clearly behind your vehicle. Hold the mirror in the center to move it up or down and side to side.

The vehicle may have an automatic dimming rearview mirror that darkens gradually to reduce the glare of headlamps from behind. Press the AUTO button located in the lower center of the mirror to turn automatic dimming on and the (off) button located next to the AUTO button to turn automatic dimming off.

One photocell on the front of the mirror senses when it is becoming dark outside. Another photocell, facing rearward, senses headlamps behind you.

To keep the photocells operating well, occasionally clean them with a cotton swab and glass cleaner.